Emergency governing apparatus



Jan. 23, 1940. P, H. KNowLToN EMERGENCY GOVERNING APPARATUS Filed May 18, 1938 Pam H. Knowhow,-

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Patented Jan. 23, 1940 UNITED STATES 2,188,187 EMERGENCY covEaNiNc APPARATUS Paul H. Knowlton, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application May 18, V1938, Serial No. 208,587

4 Claims.

This invention relates to control systems for elastic fluid power plants embodying a plurality of elastic iuid turbines adapted to receive operating fluid through a common feeder conduit and 5 more particularly to emergency governing apparatus associated. with each of the plurality of turbines for controlling the flow ofy elastic fluid to the turbines upon an abnormal operating condition obtaining with respect to any one of said turbines.

In elastic fluid power plants it is a common practice to supply elastic fluid to a plurality of relatively small turbines through a common feeder conduit or, in the case that one or more auxiliary turbines are to be operated simultaneously with a main turbine, such auxiliary turbines are also generally supplied with elastic fluid from the the same feeder conduit as supplies the main turbine. Each turbine is generally provided with emergency governing means for shutting off the supply of elastic fluid thereto upon an abnormal condition obtaining due to failure of the load, failure of the regular throttle valve or the failure of some part of the turbine itself. In power plantV 25 installations, of the type referred to, particularly those operating with extremely high pressures, the emergency control valves in the feeder conduits are generally large, complicated and costly pieces of apparatus. Hence, it is desirable to re- 30 duce the number of such valves in power plant systems where possible.

It is an object of my invention to provide a single emergency control valve in the common feeder conduit which may in turn be operated to the closed position upon the tripping of the emergency governor apparatus associated with any one of the plurality of turbines receiving operating fluid through this conduit.

It is a further object of my invention to provide an improved emergency governor apparatus for power plants of the type specified embodying a plurality of turbines supplied in parallel whereby the control is accomplished in a simple and eiiicient manner.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing. f

In the single figure of the drawing I have shown a power plant installation including a plurality of turbines adapted to be supplied with elastic fluid through a common feeder. The common feeder is provided with a control valve which is adapted to be actuated upon an abnormal condition of speed obtaining with respect to any one of said turbines.

Referring to the drawing, I and I Iare elastic fluid turbines adapted to be supplied with elastic fluid through branch feeders I2 and I3 from a 5V common feeder conduit I4. Suitable admission valves (not shown) may be provided for the throttling of the individual turbines as desired. In the common feeder conduit is provided an emergency control valve I5 shown diagrammatically in this instance as a globe valve, it being understood, however, that any suitable type of valve means is thereby represented. An operating motor II for the valve I5 is shown as comprising a cylinder I1 having a piston I8 sldably mounted therein. The stem I9 secured to the piston is connected to the Valve I5 for controlling` the position thereof. Operating fiuid for the motor is supplied through a pilot valve which comprises a cylinder 2| having valve heads 22 and 23 provided upon a stem 24 sldably arranged therein. In the well known manner, the chambers above and below the piston I8 of the operating motor I6 communicate with the pilot valve through conduits 25 and 25 respectively. Operating fluid is adapted to be supplied to the pilot valve cylinder through a connection 2'I and to be exhausted therefrom through connections 28 and 29.

The turbines III and II of the power plant are provided with similar speed responsive governor devices shown in this instance as being of the shaft embedded type mounted within bores 30 and 3l of the turbine shafts 32 and 33 respectively. The governor devices each comprise a plunger or 3 5 fly weight 34 biased toward the center of the v` shaft by means of a compression spring 35 surrounding the fly weight 34 and bearing against the disk 36 and the plug 3'I. During normal operation the y weights 34 are biased inwardly against the centrifugal force acting thereon. As the speed of either shaft rises beyond a predetermined value, the centrifugal force overcomes the biasing force of the compression spring and permits radially outward movement of the fly weight.

Tripping devices 38 and 39 are provided for the turbines IIJ and II respectively mounted adjacent the governor devices and adapted to be released as the governor fly weights are forced outwardly to effect the actuation of the emergency control valve I5. Certain elements of the tripping devices are substantially alike and will be described but once, like elementsbeing given the same reference characters in the drawing. The tripping devices include a trigger Ml pivotally mounted to tion of the plunger, the lower end thereof is;

adapted to seat upon a shoulder 41 formed on the trigger 40. A stop 48 is provided on the trigger for determining theseating area on the shoulder 41 and hence the amount of movement of the trigger required for releasing the plunger. As the trigger is rotated ina counter-clockwise direction upon the outward movement of the fly weight 34, the lower end of the plunger 43 isunseated from the shoulder and, due to the Spring 45, is. moved downwardly, the downward movement being arrested by a stop 49 positioned to engage a shoulder 50. provided on the plunger. Anoperating lever 5I is pivotally supported as at 52.- upon a stationary part 53 extending from the frame member 44. An arm oi the lever 5I is provided witha knuckle 54 which is positioned between collars 55 and 56 secured to the upper end of the operatingy plunger 43. The other end of the lever 5lis providedwith a handle 5l by means of which the tripping device may be reset. The trigger'4llis also adapted for manual tripping by means cf a lever 58 pivoted as at 59 to a stationary part G8 depending from the frame j: member 44. Tne end 6l of the manual triplever is adapted to engage apin t2 slidably supported in abore through a stationary part 53. The other n end'of the pin 62 is adapted to engage a finger 64 eiect. a shut-down of the extending from the trigger 45. The pin 52 is z normally held in a retracted position by means of a compression spring arranged between a collar 66 and the stationary part 53. By this arrangement, the station attendant upon observing an abnormal condition or for any other reason may power plant by merely raising'the left end of the lever 58. This move'- ment being transmitted through the pin t2, will cause a counter-clockwise rotation of the trigger 40 to release the actuating plunger 43.

'I'he operating lever 5I of the tripp-ing device associated with the rst turbine lll is connected by a link 68 to the pilot valve stem 24. Thus, upon the tripping of the trigger 40 of that device either by the governor fly weight 34 or by the manual trip lever 58, the operating lever 5 i'will be moved in a clockwise direction to move the pilot valve heads to the right causing operating fluid to be supplied through conduit 25 to the upper chamber of the valve operating motor It. The operating fluid will be expelled from the lower ch'ainberr of the motor 'I4 through conduit 26 whereby the control valve l5 will be actuated to the closed position.

The tripping devices associated with the other turbines such as Il are arranged for tripping the `device associated with the rst turbine upon an abnormal condition of speed obtaining with respect to such other turbines. As shown, a pressure responsive element is provided on the frame 44 of the tripping device associated with the rst turbine. This pressure responsive device includes an expansible bellows member' 69 forming a fluid tight chamber 'I0 between it and the surrounding casing 'H which is secured upon the frame 44 as by screws 12. An operating stern 'I3A secured to the movable end wall 74 of the bellows device extends through a bore in the frame member 42 and is connected to the manual trip lever 58 as at 15. The bellows member 69 and hence the stem 73 is normally biased to an upward position by means of a spring i6 mounted within the bellows around the stern 'I3 and in engagement with the end wall 14 and the frame 44. The bellows is restrained in a compressed condition by means of compressed fluid supplied to the chamber 'it by means of a conduit '11.

The fluid pressure in the conduit Tl and hence in the chamber 18 is controlled by a valve means 18. associatedwith the tripping device or" the turbine l I. As shown, this valve includes a cylinder 19 having a pair of valve heads 8i) and 8| slidably arranged therein upon a stem 42. The valve heads are normally biased to an upper position by 2 means of a spring 33 arranged between the lower valve head 8l and the end wall of the cylinder 78. With the valve heads in the upper position communication is established between a supply connection 84 and the conduit l'l and when the valve The operation of the arrangement is as follows:

Assuming that the tripping devices 38 and 39 are in the set position as shown, the valve heads of the pilot valve 2i! are so positioned that operating fluid is supplied therethrough and through conduit 26 to the lower chamber of the valve operating motor I6. The control valve l5 is thus retained in its opened position. The pressure responsive element of the tripping device associated with the rst turbine i El is restrained, that is, the bellows 69 and the spring 'l are compressed due to the pressure of the operating fluid supplied to the chamber 'm through conduit l?, the valve 'I8 and supplyl connectlon 84. Should the speed of the turbine H rise above a predetermined value. the fly weight 34 would be thrown upwardly moving the trigger 4G in a counter-clockwise direction releasing the actuating plunger 43. The operating lever 5l associated therewith would be actuated so as to move the bell crank in a clockwise direction to force the stem 82 of the control valve i8 downwardly and to establish communir cation between the conduit 'il and the drain connection 85. Due to the force of the spring l5, the bellows 69 of the pressure responsive element assoclated with the tripping device 38. would move upwardly forcing iiuid from the chamber l0. The pin 'I3 would accordingly rotate the trip lever 58 in a clockwise direction to depress the pin S22 and consequently rotate the trigger 48 in a counterclockwise direction to release the actuating plunger 43 and thereby cause movement of the valve heads of the pilot valve 20 to the right. As previously explained, this adjustment of the pilot valve heads causes the closing of the control valve l5 and the shutting down of the turbines lil and H. To reset the system it is necessary iirst to move manually the lever 5l of the tripping device 39 in a counter-clockwise direction to raise the plunger 43. As the lower end of this plunger clears the shoulder 47, the trigger `4l) automatically rotates slightly in the clockwise direction due to the force of gravity acting upon the depending finger 42. The plunger 43 is then rested upon the shoulder 4'! and is set for the next releasing operation. It Will be noted that as the lever 5I was rotated in the counter-clockwise direction the bell crank 8B was correspondinglymoved. The valve heads 80 and 8l of the valve 18 were simultaneously forced upwardly by means of the spring 83 whereupon communication was established between the iluid supply connection 84 and the conduit 11. Upon the resulting compression of the bellows of the pressure element associated with the tripping device 38, that device may subsequently be reset in a manner similar to that described in connection with the tripping device EQ, It will be noted that as the operating lever El of. the tripping device 38 is operated to reset that device, the valve heads of the pilot valve Eil are so actuated as to cause the opening of the control valve l5.

While I have described the system as adapted for controlling a power plant of only two turbines, it is obvious that substantially the same arrangement can be used for controlling a greater number of turbines similarly arranged. This can be done by merely providing the additional turbines with tripping devices similar to that used in conjunction With the turbine I l. Such devices would embody valves similar to 18 for controlling the fluid pressure in the conduit 'Vl extending to the pressure element of the tripping device 38 associated with the iirst turbine. The arrangement shown is extremely simple in design and reliable in operation. Due to the fact that most of the structural parts of the tripping devices 38 and 39 are alike, such parts may be interchanged as desired, and the matter of assembly, adjustment and replacement of parts of the respective devices is accordingly simplified.

Having described the method of operation of my invention together With the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustraive and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An emergency control apparatus for fluid systems comprising a plurality of tripping devices each including a condition responsive means, a trigger adapted for actuation by said condition responsive means, a manually operable trip` lever for actuating said trigger, and a spring biased actuating means adapted to be released upon actuation of said trigger, an emergency control lever actuable by the spring biased actuating means of one of said plurality of tripping devices, `and means responsive to the actuation of the trigger of the other of said tripping devices for actuating the trigger of said one device, said last mentioned means adapted to preclude resetting of said emergency control lever until the other tripping devices have been reset.

2. A fluid control system comprising a plurality of emergency tripping devices, each of said devices including means responsive to a predetermined condition, a trigger adapted to be ac'- tuated b y said condition responsive means, a manually operable trip lever for said trigger, and spring biased actuating means adapted to be released upon the tripping of said trigger, pressure responsive means associated with the rst of said devices for tripping the trigger thereof, valves for controlling said pressure responsive means operable by the other of said plurality of tripping devices, an emergency control lever adapted to be actuated upon the release of the spring biased actuating means of said first device, said control lever being manually operable for resetting said rst device.

3. A iiuid control system comprising a plurality of emergency tripping devices, each of said devices including means responsive to a predetermined condition, a trigger adapted to be actuated by said condition responsive means, a manually operable trip lever for said trigger, and a spring biased actuating means adapted to be released upon actuation of said trigger, pressure responsive means for actuating the trip lever of the first of said tripping devices, control means for said pressure responsive means associated with the second of said tripping devices and a control lever associated With the first of said tripping devices and adapted to be actuated upon the tripping of either of said devices.

f4. Fluid control apparatus comprising a pair of tripping devices each including a condition responsive means, a trigger adapted for actuation by said condition responsive means, a manually operable trip lever for actuating said trigger, and a spring biased actuating means adapted to be released upon actuation of said trigger, the first of said tripping devices having a pressure responsive means for actuating said trip lever, control means for said pressure responsive means operable by the spring biased actuating means of the second of said devices, an emergency control lever operable by the spring biased actuating means of said first device upon the tripping of i the trigger of said first tripping device.

PAUL H. KNoWLToN. 

